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Test ID URIC Uric Acid, Serum

Reporting Name

Uric Acid, S

Useful For

Diagnosis and treatment of renal failure

 

Monitoring patients receiving cytotoxic drugs and a variety of other disorders, including gout, leukemia, psoriasis, starvation and other wasting conditions

Specimen Type

Serum


Necessary Information


Patient's age and sex are required.



Specimen Required


Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Specimen Volume: 0.5 mL

Submission Container/Tube: Plastic vial

Collection Instructions:

1. Serum gel tubes should be centrifuged within 2 hours of collection.

2. Red-top tubes should be centrifuged and aliquoted within 2 hours of collection.


Specimen Minimum Volume

0.25 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 7 days
  Frozen  180 days

Reference Values

Males

1-10 years: 2.4-5.4 mg/dL

11 years: 2.7-5.9 mg/dL

12 years: 3.1-6.4 mg/dL

13 years: 3.4-6.9 mg/dL

14 years: 3.7-7.4 mg/dL

15 years: 4.0-7.8 mg/dL

≥16 years: 3.7-8.0 mg/dL

Reference values have not been established for patients who are <12 months of age.

 

Females

1 year: 2.1-4.9 mg/dL

2 years: 2.1-5.0 mg/dL

3 years: 2.2-5.1 mg/dL

4 years: 2.3-5.2 mg/dL

5 years: 2.3-5.3 mg/dL

6 years: 2.3-5.4 mg/dL

7-8 years: 2.3-5.5 mg/dL

9-10 years: 2.3-5.7 mg/dL

11 years: 2.3-5.8 mg/dL

12 years: 2.3-5.9 mg/dL

≥13 years:  2.7-6.1 mg/dL

Reference values have not been established for patients who are <12 months of age.

Day(s) Performed

Monday through Sunday

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

84550

Clinical Information

Uric acid is the final product of purine metabolism in humans. Purines, compounds that are vital components of nucleic acids and coenzymes, may be synthesized in the body or they may be obtained by ingesting foods rich in nucleic material (eg, liver, sweetbreads). Approximately 75% of the uric acid excreted is lost in the urine; most of the remainder is secreted into the gastrointestinal tract where it is degraded to allantoin and other compounds by bacterial enzymes.

 

Asymptomatic hyperuricemia is frequently detected through biochemical screening. The major causes of hyperuricemia are increased purine synthesis, inherited metabolic disorder, excess dietary purine intake, increased nucleic acid turnover, malignancy, cytotoxic drugs, and decreased excretion due to chronic renal failure or increased renal reabsorption. Long-term follow-up of these patients is undertaken because many are at risk of developing renal disease; few of these patients ever develop the clinical syndrome of gout.

 

Hypouricemia, often defined as serum urate below 2.0 mg/dL, is much less common than hyperuricemia. It may be secondary to severe hepatocellular disease with reduced purine synthesis, defective renal tubular reabsorption, overtreatment of hyperuricemia with allopurinol, as well as some cancer therapies (eg, 6-mercaptopurine).

Interpretation

Hyperuricemia is most commonly defined by serum or plasma uric acid concentrations above 8.0 mg/dL in males or above 6.1 mg/dL in females.

Cautions

The following drugs cause interference (falsely decreased levels) at therapeutic concentrations:

-Alpha-methyldopa

-Desferoxamine

-Calcimdobesilate

 

Results can be falsely decreased in patients with elevated levels of N-acetyl-p-benzoquinone imine (NAPQI, a metabolite of acetaminophen), N-acetylcysteine (NAC), and metamizole.

Clinical Reference

Tietz Textbook of Clinical Chemistry. Chapter 24: Fourth edition, Edited by CA Burtis, ER Ashwood, WS Bruns. WB Saunders Company, Philadelphia, 2006, pp 803-807

Method Description

Uric acid is oxidized by uricase to form allantoin and hydrogen peroxide. The hydrogen peroxide reacts with TOOS (N-ethyl-N-[2-hydroxy-3-sulfopropyl]-3-methylaniline) and 4-aminophenazone in the presence of peroxidase to form a quinone-imine dye. The intensity of the red color formed is proportional to the uric acid concentration. Prior to the start of the reaction, the sample is initially incubated with a reagent mixture containing ascorbate oxidase and a clearing system. This eliminates any ascorbic acid present in the sample which could interfere with the peroxidase indicator reaction.(Package insert: Roche Uric Acid reagent, Roche Diagnostic Corp., Indianapolis IN, V10. 12/2018)

Report Available

Same day/1 to 2 days

Reject Due To

Gross hemolysis Reject

NY State Approved

Yes

Method Name

Photometric, Uricase/Quinone-Imine Dye Formation

Forms

If not ordering electronically, complete, print, and send a Renal Diagnostics Test Request (T830) with the specimen.